Generally, an excavating machine such as an excavator excavates, for example, a ground of a working object when an operator who is operating personnel operates an operation lever to drive a work machine including a bucket. For example, Patent Literature 1 discloses a technique of detecting blade edge positions of a bucket, determining a relationship between an absolute position of an underground pipe and absolute positions of bucket blade edges and determining an excavation position and an excavation depth by a bucket by means of an excavation position/depth determination unit.